Kite balloons have been used for industrial, scientific, military, and advertising purposes since being reduced to practice by August von Parseval over a century ago, carrying people, weather instruments, radar, advertising signs, etc. Since the beginning, designers have experimented with varying levels of aerostatic and aerodynamic lift. Currently, development in the art focuses on three main aspects of kite balloons:
Envelope.
While a large variety of materials, configurations, and construction methods for kite balloons are known, only four envelope shapes have been widely experimented with, and only two are currently available commercially:                (a) Cylindrical balloons (Parseval-type, see, e.g., U.S. Pat. No. 970,262). These were largely abandoned after the invention of (b).        (b) Blimp-shaped balloons (Caquot and later, see e.g., U.S. Pat. No. 1,419,205), including most contemporary aerostats.        (c) V-shaped balloons (NOAA's Dart balloon, Menke), were explored in the 1960's but largely abandoned due to poor aerostatic lift performance.        (d) Lenticular, or oblate spheroid balloons (see, e.g., U.S. Pat. Nos. 4,919,365 and 5,065,163 to Arthur W. MEARS), which are successfully marketed by Skystar, Allsopp Helikite, and others.        
Note that blimp-type aerostats have reduced performance at small sizes due to the unfavorable relationship of surface area to volume as size is reduced. Small kite balloons with more spherical blimp shapes are sometimes used (see, e.g., U.S. Pat. No. 1,377,924), and lenticular envelopes are generally preferred at smaller sizes (less than about 100 cu. ft.) because of their greater volume for a given surface area, increased kiting lift, and simplicity of fabrication. However, lenticular envelopes introduce known issues through their fore/aft symmetry and two-part pattern (see Kiting and Rigging, below.)
Envelope Fabrication.
The easiest way to make an air-tight seam is to seal it on a flat surface, and various schemes have been devised to construct balloon seams on flat surfaces in whole or part, singular or multiple. The simplest balloon patterns seal and cut the envelope with a single step on a flat surface (see, e.g., U.S. Pat. Nos. 1,625,394 and 4,290,763). Lenticular kite balloons in particular are simple to fabricate because a flat, circular pattern can be used.
Kiting.
In the early history of kite balloons, kiting—inclining the balloon into the wind to derive aerodynamic lift—was achieved by balancing the payload towards the rear of the balloon. In later and larger designs, the payload was balanced forward, around the bridle (see, e.g., U.S. Pat. Nos. 1,377,924 and 1,686,646) and towards the nose of the balloon to create a forward mass balance that automatically weather cocks.
A forward mass balance is possible because of the fore/aft asymmetry of the blimp balloon shape. Small blimp-shape kite balloons such as. Domina Jalbert's Kytoon (see, e.g., U.S. Pat. Nos. 2,398,744 and 2,398,745), an emergency radio buoy designed for life rafts (1940's-60's), and CNES's Aeroclipper (1990's-today) use kiting (see, e.g., U.S. Pat. No. 5,115,997) with a forward mass balance. Lenticular designs such as the Skystar and Allsopp Helikite (see, e.g., U.S. Pat. No. 6,016,991 to Gerald ALLSOPP, and U.K. Patent Application No. GB2,280,381A by the same inventor) with their fore/aft symmetry, must have a rearward mass balance if they are to maintain an appropriate flight angle when not under a wind load. The increased static lift and increased kiting surface provided by a lenticular envelope must be balanced against its negative characteristics for weathercocking.
Rigging.
One of the primary difficulties in operating a kite balloon is both bridle rigging and payload rigging. Multiple lines and systems to distribute stress constitute a significant portion of the fabrication work of a balloon and the long-term maintenance needed. Furthermore, adjusting and checking the symmetry of bridles are challenging tasks for even moderately trained users.
Keeled kites dominate the consumer kite market (e.g. Delta kites of the Rogallo design, e.g. U.S. Patent Nos.) because they do not need adjustment to maintain their stabilizing position. Simplified rigging increases the chance of successful flight by inexperienced kite fliers. Kite balloons with tether-tensioned keels requiring multiple bridle lines date from the Parseval device and were explored by Upson (U.S. Pat. Nos. 1,341,248 and 1,385,972) and Yamada, and others as a means of stability before being superseded by inflated and ram-air fins. Fixed keels have been explored by Mears and Allsopp, however their position is a departure from best practices.
Kite balloons are usually bridled around their horizontal centerline, which prevents rolling and distributes line tension into pressure along the envelope's major axis to resist wind force on the nose. The multi-gore pattern of a Blimp-type kite balloon separates the relatively weaker seams from mounting points for both stabilizers and rigging attachments around the envelope's horizontal centerline. On a two-part lenticular balloon, the seam and the distortion around it dominates the horizontal centerline, preventing stabilizers and rigging from being attached directly to the envelope in this area. Mears-type drag-net stabilizer balloons may use a system of restraining straps to place re-enforced rigging attachments around the envelope's center, while the Helikite uses a central keel for rigging and creates nose pressure and manages roll by other means.
Innovations combining simplified rigging around the horizontal center of a balloon with the simplified fabrication, volumetric efficiency, and aerodynamic lift of a lenticular balloon as well as the fore/aft asymmetry of a blimp-type balloon would provide significant value to the field of small kite balloons.